This invention relates to an improved shirred stick of tubular food casing and more particularly to a shirred stick of tubular food casing having an end closure, and to a method and apparatus for making the same.
Man-made tubular food casings, particularly food casing prepared of regenerated cellulose, are used extensively in the manufacture of sausage products such as skinless frankfurters and the like. In general, these casings are prepared as hollow, thin-walled tubes of very great length. In practice, tubular casings of lengths ranging from about 12 to 49 meters or more are shirred and compressed to produce what is commonly termed in the art "shirred casing sticks or strands" of from about 20 to 70 cm. in length.
After shirred casing sticks are prepared, they are packaged and shipped to a food processor where individual sticks of casing are placed on stuffing horns and stuffed with food emulsion filling the casing to its fully extended length. Such casing sticks may be stuffed by manual or automatic operation.
Automated machines have been developed for the stuffing and/or stuffing and linking of shirred food casings with meat emulsion in the making of frankfurters, and the use of these machines, as, for example, disclosed in Townsend U.S. Pat. No. 3,115,668, has greatly increased the production rate of sausage product.
Heretofore, when the food casing was stuffed manually, the operator would deshirr a short length of casing from the end thereof and effect a closure to prevent the meat emulsion extruded into the shirred casing from being lost from the open end thereof. In the automated stuffing machines, the shirred casing sticks are fed automatically and rapidly onto the stuffing horn and it is required that the fore end of the casing stick have a plug or closure so as to effectively block the flow of food emulsion therefrom. Providing a casing having an end plug or closure formed therein generally can be more uniformly and economically accomplished during casing manufacture than during use of the casing. Various types of casing closures and methods for forming the same are known and have been disclosed, for example, in U.S. Pat. Nos. 3,162,893 to Townsend, 3,274,005 to Alsys, 3,383,222 to Alsys et al., and 3,419,401 to Matecki.
Although these casing end closures exhibit many advantages over the manually formed closures, they have been found to have certain limitations such as not being readily formable on shirring machines, being difficult to control the amount of casing used in forming the end closure, being too tightly anchored in the bore, being too rigid to be employed in some versions of the automatic linking means of stuffing machines, or unfolding or everting in a non-uniform or non-symmetric manner.
Accordingly, it is one object of this invention to provide a new and improved method of closing the fore end of a shirred casing stick for food or other materials.
Another object of this invention is to provide an improved method for closing the end of a shirred casing stick utilizing only the material of the casing in the closure.
Another object of the invention is to provide a new and improved method of producing closures for hollow shirred sticks of tubular casings.
Yet another object of the invention is to provide an end closure which is readily and uniformly extended or caused to evert by the injection of food emulsion into the casing.
Yet another object of the invention is to provide an end closure which is formed without damaging the casing material.
Still another object of this invention is to provide a new and improved device for practicing the aforesaid methods.
Other and additional objects of the invention will become apparent from the specifications, description and accompanying drawings.